Portable welding apparatus



Oct. 25, 1932. E, J, wf RAGSDALE 1,884,222

PORTABLE WELDING APPARATUS Filed June 16, 1930 35 l N VEN TOR.

EARL l W. RAG sDAurz.

BY A

WM ATTORNEY.

y Petented oer. Y25, 1932 UNITED STATES PATENT OFFICE EARL J'. W.BAGSDALE, 0l' N ORRISTOWN, PENNSYLVANIA, ASSIGNOB TO EDWARD G. BUDDMANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVAN A CORPORATION orPENNSYLVANIA -I PORTAPLEVWELDING APPARATUS Application led June 16,

This invention relates to electric welding apparatus and in general to aportable weldin machine adapted for spot welding the adJacent faces ofsheet metal sections to each other. The invention is primarily concernedwith an electric resistance weldingmachine adapted to make a weld eitherin one spot or to make a weld in a series of separate spots, or in spotsoverlapping each other so as to form a seam weld according to thepositioning of the work to be welded between the electrodes of thewelding apparatus. Electric resistance welding machines of this type arecommonly known and comprise in general a fixed electrode and a movableelectrode in line with and co-acting with the fixed electrode. The twoelectrodes are suitably connected with a source of welding current andthe work is placed between the electrodes and the movable electrode isactuated tp approach the work and clamp thesame firmly against the fixedelectrode so that a circuit is completed between the two electrodes andthrough the work. In this form of machine the electrodes serve asclamping members and as such, considerable pressure is maintained duringthe welding o eration between the electrodes and the wor therebyresulting in undue wear upon the electrodes and sometime inmal-adjustment brought about by this common ractice of utilizing them asclamping mem ers.

The principal object of the invention is to provide an electricresistance welding ma chine in which the pressure necessary for thelwelding operation is lessened by the provision of a means for clampingthe work adjacent the area to be. welded independently of the pressureexerted by the opposed electrode, thus reducing the wear upon theelectrodes and the mal-adjustment brought about in common practice byutilizing these elev ments as clam ing members.

Another obiect of the invention is to provide a portab e machine whichis adapted to do seam welding uponwork of irregular or warped formation.

In welding of this nature, it frequently happens that where adjacentfaces of two sections of sheet metal are positioned one naso.` semi No.461,478.

against the other, preparator'. to performing A the welding operation,the a acent faces do not contact with each other throughout the area atwhich the weld Ais to take lace, with the consequent result that when te current is completed through the two electrodes and through the work,this current does not flow directly through the work from one electrodeto the other because of the existence of an air pocket between theadjacent faces of the work. Consequently the current fiows around thisair pocket from one electrode to the other, causing an imperfect weld.In order to obviate this diticulty in welding, the present inventioncontemplates the provision of a portable welding apparatus havingopposed electrodes adapted to engage the work therebetween and apply aresistance current to the same, provision being made, whereby the workmay be rmly compressed to drive out any existing air pockets and topresent abutting opposed faces in the work through which current maydirectly flow from one electrode to the other to form a perfect andsound weld.

An additional object of the invention is to provide a portable weldingapparatus in which a constant pre-determined pressure is applied toopposing sides of the work by the electrodes to insure uniformity ofsuccessive welds, while at the same time a greater pressure is appliedon opposin sides of the work by a means independent ot the electrodesfor clamping the work together and eliminating or destroying existingair pockets between the work.

A still further object of the invention is to provide aportable'electric welding apparatus which is extremely rugged in itsconstruction and which is readily dis-assembled for renewal of theelectrodes or replacement of parts. Convenienceof arrangement of partscomparative inexpense of manufacture, an extreme efficiency of operationare further desiderata which have been borne in mind in the productionand development of the prescnt invention.

In the accompanying single sheet of drawings, forming a part of thisspecification and in which drawings similar characters of refbled erenceare employed to designate similar parts throughout, one embodlment ofthe present invention is shown, and in this sheet of drawings,

Fig. 1 is a pers ective view of the assembled portable wel ingapparatus.

Fig. 2 is a side elevation of the assembled device, certain parts beinrrremoved for the purpose of more clearly illustrating the nature of theinvention.

F igl. 3 is a bottom plan view of the assemevice; and

Fig. 4 is a fragmentary view diagrammatically illustrating the manner inwhich efficient welding is accomplished.

In the form of welding apparatus herein illustrated, and as illustrativeof all of such welding machines now in general use, a pair of op sedelectrode elements are shown at 10 an 11. These two electrodesareadapted to be suitably connected with a source of welding current whichmay be, for example, the secondary terminals of a transformer. To thisend the lectrode 11 is provided with a socket 14 ada ted to receive aterminal of one of the lead-1n wires coming from the secondar of thetransformer. The work is place between the two electrodes and by meansof an actuating mechanism, the electrodes are caused to approach eachother and at an opportune moment the current is applied so that acircuit is completed between the two electrodes and through the work.The resistance of the work to the passage of the electric currentquickly raises it to such a temperature that the pieces of sheetmaterial are welded together at the point where pressure is applied bythe electrode.

In the present instance the electrode 10 is rovided with a flat surface16 to which is bolted by means of cap screws 18, a lead-in connection 20formed of laminated stri s of copper and adapted to suply current om oneterminal of the secon ary of the transformer. This electrode is providedwith a removable tip in the form of a plate 13 securedby cap screws 15to the main body of the same, and this tip lpclijects slightly over theed e of themain y of the electrode towar the electrode 11 in order thatits projecting gprtion will contact with the work to pass t e currentthrough the same to the other electrode. .Electrode 10 is pivotedbetween a gair of parallel side bars 30 and 32, which si e bars are svaced from each other at one end by means o a spacer bar 34 and at theother end by means of the electrode -11,

which latter electrode is removably secured in,

osition between the two side bars' 3 0 and 32 y means of ca screws 35.This electrode 11 is provided witlh a projecting portion 36 considerablywider than, butv opposing, the projecting portion on the removableelectrode tip f .As stated above, the electrode 10 is pivot-VA allymounted between theside bars 30 and 32, and to this end a face plate 40secured b cap nuts 41, to the side bar 30 has extendingt erethrough aset screw 42 extending into a recess 43 in one side of the electrode 10.Extending through the side member 32 is a plu member 44 having avshoulder 45 thereon adapted to be clamped against the inner side of themember 32 by means of a nut and washer arrangement 46. This plug member44 has a second shoulder 47 thereon which is provided centrally with acenter point 48 ex tending into a recess 49 in one side of the electrode10. Thus it will be seen that the electrode is adjustably centered fortiltin movement between the side members 30 an The electrode 10 isadapted to be tilted so that the projecting portion of the electrode ti13 will contact with one side of the vwork an in order to rovide amanual means for so tilting the e ectrode, an operatin lever is shown at50. This lever is provi ed with a wrist portion 51 which is a counterart of an extended ortion of the side mem ers 30 and 32 and thls portion51, together with such counterart, forms a handle grip for the operatoro the device. The wrist portion 51 of the lever 50 isveneered with Woodor the like.

The lever 50 is shown as beinor U-shapcd in cross section throu h thewrist portion 51 and as having a re uced portion 52 also U- sha ed incross section through which the stu 44 extends, and thus the lever ismounted for tween t e shoulder 47 on the stud 44 and the side member 32.The forward edge of the wrist portion 51 is provided with a downwardlyextending flange 53 and extending through the downwardly extended flangeis a threadedly adjustable cap screw 60. This cap screw extends into theelectrode element 10 and the electrode element 10 is normally urged awayfrom the forward face of the handle member 51 by means of a coil sprin55 disposed between this element and sai forward face until suchmovement away from the forward face is limited by the head of the cascrew 60. The wrist member 51 is norma ly urged upwardly from themembers 30 and 32 by means of a coil spring disposed about a spacingcollar extendin between the side members 30 and 32 and hel in posi.-tion by means of a bolt 62 extendin" through the collar and secured inposition lby means of a nut 63.

From the-arrangement of parts thus far described it will be seen that asthe wrist portion 51 is depressed, the electrode 10 is first urgedagainst the work to exert on the same a pressure equal only to thetension of the coil spring 55, regardless of the pressure placed uponthe wrist member 51. In order to compress the work to provide forellicient welding, a pressure member is disposed between pivotalmovement on the stud 44 be-A the parallel sides of the U-shaped reducedportion 52 of the lever 50. This member is best disclosed in Fig. 1 andis in the form of a comparatively narrow block havin portion 82 ada tedto bear agamst the work on they electro e 11 when the wrist member 51 isdepressed to advance the depending flange 53 toward the work. Thedownward movement of the wrist member 51 is limited by the member 8O forwhen the surface 82 on the member 80 contacts with the work, thepressure on the wrist member 51 is imparted to the Work in a degreecommensurate with the law of leverages. The force of compressionmaintained by the coil spring 55 upon the electrode, and consequentl thepressure of this electrode upon the wor t, will be constant regardlessof the pressure applied to the wrist member 51. The member 80 beingpositioned adjacent the electrode 10 and being opposed to the electrode11, will compress the work to a degree limited only by the strength ofthe o erator, and thus the worlt will b e securely c amped for thewelding operation, While the electrode member 10 will press against thework with a pressure pre- Y determined by the judgment of the operator'and consequently effective Welding will take place; The actual weldingoperation itself may be performed by closing a switch momentarily to.permit current to flow from the one terminal of the secondary of thetransformer i to the other terminal through the work. It is not deemedadvisable to apply the voltages constantly to the electrodes.

The electrodes are properly insulated from each other. This insulatingof the electrodes is effected by forming the side members 30, andpreferably the compression member 8O of some suit-able insulatingmaterial having a degree of strength and toughness sufficient to.withstand the usages required of it. While these elements may be formedof any suitable material and in any suitable manner, they are preferablyformed of some composition such as bakelite or fibre on account of thedurability andl ruggedness of these elements.4 'f However, irrespectiveof these details, in

arrangement ofparts shown in the .accom-f panying sheets of drawings ordescribed 1n manufacture, the essential features of the invention arealways preserved.

In actual use the fixed electrode 11 andremovable electrode 10, togetherwith the underneath side of the side bars adjacent these electrodes forma guide for the work and the operator, by sli ing the portable apparatusalong the peripher of the work is enabled to perform thq we dinoperation at points ually spaced from t e edge of the work.'I

T e device is of such size that the operator may perform the weldingoperation with one hand, if desired.

I do not desire to limit myself to the exact the specification. Y Onlyin so far as the invena flat front tion is pointed out in theaccompanying claims is the same to be limited.

YWhat I claim is:

1. In a portable apparatus for welding sheet material together, astationary electrode and a movable electrode normally spaced from saidstationary electrode, a lever resiliently engaging said movableelectrode and adapted' upon depression to urge the same against a sheetof material disposed between said electrodes, and a Aclamping memberrigidly secured to saidlever and adapted upon depression of said leverto compress the sheet material adjacent the area of engagement of thesheet material between said electrodes.

2. A portable apparatus for welding sheet l and clamping member beingadapted to simultaneously engage a sheet of material disposed in contactwith said stationary electrode, means for resiliently urging saidmovable electrode against said sheet material to form an electricalcontact therewith, and for positively urging said clamping memberagainst said sheet material to compress the same.

3. In a portable apparatus for welding sheet material together, astationary electrode anda movable electrode, a clamping member, saidmovable electrode and clamping member normally occupying a positionspaced from said stationary-electrode to permit insertion of a sheet ofmaterial to be welded between said stationary electrode and said movableelectrode and clamping member. means for resiliently urging said movableelectrode toward said stationary electrode to establish contact with thesheet of material disposed therebetween, and for urging said clampingmember toward said stationary electrode for clamping the sheet ofmaterial therebetween.

4. In a portable apparatus for welding sheet material together, astationary electrode and a movable electrode, a, clamping member, saidmovable electrode and clamping member normally occupying a positionspaced from said stationary electrode to permit insertion of a sheet ofmaterial toibe welded between said stationary electrode and said movableelectrode and clamping member, a plate secured to said clamping member,a spring disposed between said plate and movable elecv trode, wherebymovement of said plate normally urging said clamping member toward saidstationary electrode will vcause yielding pressure of the movableelectrode upon the sheet'of material disposed between the same and saidstationary electrode.

5. An apparatus for welding sheet material together comprising, incombination, a pair of ,Y

electrodes, means for yieldingly urging one termined degree of pressure,and a pressure of said electrodes against a sheet of material membersecured to said plate and adapted disposed between said electrodes, andmeans upon movement of said plate toward said independent of saidelectrodes for clamping movable electrode to engage the material to thesheet of material directly against the other compress the same adjacentsaid movable electrode. electrode.

6. In a welding machine, the combination l0. A welding machinecomprising a sta- .withfa stationary electrode of a movable electionarycontact electrode, a movable contact trode, means for causing saidmovable elec- Velectrode of relatively smaller contact area trode toengage the sheet material and clamp than said stationary electrode andarranged the same against said stationary electrode to be moved againsta plurality of overlapfor passing electric current therethrough, pingsheets disposed between said electrodes, and additional means adjacentsaid movable a clam infr member adjacent the movable electrode forIclamping the sheet material electro e directly oppositea portion of theagainst said stationary electrode to compress relatively llrge opposedarea ofk the stationthe same directly therebetween. ary electrode andarranged to be moved 7. In a welding machine, the combination againstsaid sheets to clamp the same directly with a stationary electrode of amovable elecagainst said opposed portion of the stationary trede adaptedto coact with said stationary electrode.

electrode to engage the material to be welded In testimony whereof Ihereunto ailix my therebetween, of means for causing said movsignature.

able electrode to engage the sheet material EARL J. W. RAGSDALE. andapply a pressure thereto not in excess of the pressure required toestablish an electrical contact with the material, and means independentof said movable electrode for clamping the sheet material adjacent saidelectrode directly against said stationary electrode.

8. In a welding machine, a stationary electrode .having a pair oflarallel side bars attached thereto, a mova le electrode pivoted betweensaid side bars, said movable electrode having a contact surface thereonadapted upon pivotal movement of the movable electrode to engage a sheetof material and clamp the same against said stationary electrode to passa welding current therethrough, a plate adjacent said movable electrode,means normally maintaining said movable electrode out of contact withthe mate-rial to be welded, resilient means disposed between said plateand said movable electrode adapted upon movement of said plate towardsaid movable electrode to engage the work with a pre-determined degreeof pressure, and means independent of said last-mentioned means forclamping the sheet of material adjacent said movable electrode.

9. In a welding machine, a stationary elec-` trode having a pair ofparallel side bars attached thereto, a movable electrode pivoted betweensaid side bars, said movable electrode having a contact surface thereonadapted upon pivote-d movement of the movable electrode to engage asheet of material and clamp the same against said stationary electrodeto pass a welding current therethrough, a plate adjacent said movableelectrode, means normally maintaining said movable electrode out ofcontact with the material to be welded, resilient means disposed betweensaid plate and said movable electrode adapted upon movement of saidplate toward Vsaid movable electrode to engage the work with a pre-de-

